效果图

效果图

• 显示年份

具体代码

写两个分类 Category

NSCalendar的分类

#import <Foundation/Foundation.h>

@interface NSCalendar ()

+ (instancetype)calendar;

@end

#import "NSCalendar+WMCategory.h"

@implementation NSCalendar ()

+ (instancetype)calendar {
    if ([NSCalendar respondsToSelector:@selector(calendarWithIdentifier:)]) {
        return [NSCalendar calendarWithIdentifier:NSCalendarIdentifierGregorian];
    }else {
        return [NSCalendar currentCalendar];
    }
}
@end

NSDate的分类

#import <Foundation/Foundation.h>

@interface NSDate ()

/**
 *  是否为今年
 */
- (BOOL)isThisYear;

/**
 *  是否为今天
 */
- (BOOL)isToday;

/**
 *  是否为昨天
 */
- (BOOL)isYesterday;

/**
 *  是否为明天
 */
- (BOOL)isTomorrow;

@end

#import "NSDate+WMCategory.h"
#import "NSCalendar+WMCategory.h"

@implementation NSDate ()

// 今年
- (BOOL)isThisYear {
    
    // 判断self这个日期是否为今年
    NSCalendar *calendar = [NSCalendar calendar];
    // 年
    NSInteger selfYear = [calendar component:NSCalendarUnitYear fromDate:self];
    NSInteger nowYear = [calendar component:NSCalendarUnitYear fromDate:[NSDate date]];
    return selfYear == nowYear;
}

// 今天
- (BOOL)isToday
{
    // 判断self这个日期是否为今天
    NSCalendar *calendar = [NSCalendar calendar];
    // 获得年月日元素
    NSCalendarUnit unit = NSCalendarUnitYear | NSCalendarUnitMonth | NSCalendarUnitDay;
    NSDateComponents *selfCmps = [calendar components:unit fromDate:self];
    NSDateComponents *nowCmps = [calendar components:unit fromDate:[NSDate date]];
    return selfCmps.year == nowCmps.year
    && selfCmps.month == nowCmps.month
    && selfCmps.day == nowCmps.day;
}

// 昨天
- (BOOL)isYesterday
{
    // 判断self这个日期是否为昨天
    // self == 2015-10-31 23:07:08 -> 2015-10-31 00:00:00
    // now  == 2015-11-01 14:39:20 -> 2015-11-01 00:00:00
    NSDateFormatter *fmt = [[NSDateFormatter alloc] init];
    fmt.dateFormat = @"yyyyMMdd";
    NSString *selfString = [fmt stringFromDate:self]; // 20151031
    NSString *nowString = [fmt stringFromDate:[NSDate date]]; // 20151101
    NSDate *selfDate = [fmt dateFromString:selfString]; // 2015-10-31 00:00:00
    NSDate *nowDate = [fmt dateFromString:nowString]; // 2015-11-01 00:00:00
    NSCalendar *calendar = [NSCalendar calendar];
    NSCalendarUnit unit = NSCalendarUnitYear | NSCalendarUnitMonth | NSCalendarUnitDay;
    NSDateComponents *cmps = [calendar components:unit fromDate:selfDate toDate:nowDate options:0];
    return cmps.year == 0
    && cmps.month == 0
    && cmps.day == 1;
}

// 明天
- (BOOL)isTomorrow
{
    NSDateFormatter *fmt = [[NSDateFormatter alloc] init];
    fmt.dateFormat = @"yyyyMMdd";
    NSString *selfString = [fmt stringFromDate:self]; // 20151031
    NSString *nowString = [fmt stringFromDate:[NSDate date]]; // 20151101
    NSDate *selfDate = [fmt dateFromString:selfString]; // 2015-10-31 00:00:00
    NSDate *nowDate = [fmt dateFromString:nowString]; // 2015-11-01 00:00:00 
    NSCalendar *calendar = [NSCalendar calendar];
    NSCalendarUnit unit = NSCalendarUnitYear | NSCalendarUnitMonth | NSCalendarUnitDay;
    NSDateComponents *cmps = [calendar components:unit fromDate:selfDate toDate:nowDate options:0];
    return cmps.year == 0
    && cmps.month == 0
    && cmps.day == -1;
}
@end

在模型里面使用(根据具体需求来写)

• 模型WMTopic.m文件

#import "WMTopic.h"
#import "NSCalendar+WMCategory.h"
#import "NSDate+WMCategory.h"

@implementation WMTopic

static NSDateFormatter *fmt_;
static NSCalendar *calendar_;
/**
 *  在第一次使用这个类的时候调用1次
 */
+ (void)initialize {
    fmt_ = [[NSDateFormatter alloc] init];
    calendar_ = [NSCalendar calendar];
}

- (NSString *)created_at // 表示时间的成员属性的get方法
{
    // 获得发帖日期
    fmt_.dateFormat = @"yyyy-MM-dd HH:mm:ss";
    NSDate *createdAtDate = [fmt_ dateFromString:_created_at];
    if (createdAtDate.isThisYear) { // 今年
        if (createdAtDate.isToday) { // 今天
            // 手机当前时间
            NSDate *nowDate = [NSDate date];
            NSCalendarUnit unit = NSCalendarUnitYear | NSCalendarUnitMonth | NSCalendarUnitDay | NSCalendarUnitHour | NSCalendarUnitMinute | NSCalendarUnitSecond;
            NSDateComponents *cmps = [calendar_ components:unit fromDate:createdAtDate toDate:nowDate options:0];
            if (cmps.hour >= 1) { // 时间间隔 >= 1小时
                return [NSString stringWithFormat:@"%zd小时前", cmps.hour];
            } else if (cmps.minute >= 1) { // 1小时 > 时间间隔 >= 1分钟
                return [NSString stringWithFormat:@"%zd分钟前", cmps.minute];
            } else { // 1分钟 > 分钟
                return @"刚刚";
            }
        } else if (createdAtDate.isYesterday) { // 昨天
            fmt_.dateFormat = @"昨天 HH:mm:ss";
            return [fmt_ stringFromDate:createdAtDate];
        } else { // 其他
            fmt_.dateFormat = @"MM-dd HH:mm:ss";
            return [fmt_ stringFromDate:createdAtDate];
        }
    } else { // 非今年
        return _created_at;
    }
}
@end